A case study suggested that a deficiency in myophosphorylase may be linked with cognitive impairment. Besides muscle, this isoform is present in astrocytes, where it plays a key role in neural energy metabolism. A 55-year-old woman with McArdle disease has expressed cognitive impairment with bilateral dysfunction of prefrontal and frontal cortex. Further studies are needed to assess the validity of this claim.[2]

1.
Entrez
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The name Entrez was chosen to reflect the spirit of welcoming the public to search the content available from the NLM. Entrez Global Query is a search and retrieval system that provides access to all databases simultaneously with a single query string. Entrez can efficiently retrieve related sequences, structures, and references, the Entrez system can provide views of gene and protein sequences and chromosome maps. Some textbooks are available online through the Entrez system. The Entrez front page provides, by default, access to the global query, all databases indexed by Entrez can be searched via a single query string, supporting boolean operators and search term tags to limit parts of the search statement to particular fields. This returns a unified results page, that shows the number of hits for the search in each of the databases, Entrez also provides a similar interface for searching each particular database and for refining search results. The Limits feature allows the user to narrow a search a web forms interface, the History feature gives a numbered list of recently performed queries. Results of previous queries can be referred to by number and combined via boolean operators, search results can be saved temporarily in a Clipboard. Users with a MyNCBI account can save queries indefinitely and also choose to have updates with new search results e-mailed for saved queries of most databases and it is widely used in the field of biotechnology as a reference tool for students and professionals alike. Entrez searches the following databases, PubMed, biomedical literature citations and abstracts, including Medline - articles from journals, in addition to using the search engine forms to query the data in Entrez, NCBI provides the Entrez Programming Utilities for more direct access to query results. The eUtils are accessed by posting specially formed URLs to the NCBI server, there was also an eUtils SOAP interface which was terminated on July 2015. In 1991, entrez was introduced in CD form, in 1993, a client-server version of the software provided connectivity with the internet. In 1994, NCBI established a website, and Entrez was a part of initial release. In 2001, Entrez bookshelf was released and in 2003, the Entrez Gene database was developed, Entrez search engine form Entrez Help

2.
National Center for Biotechnology Information
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The National Center for Biotechnology Information is part of the United States National Library of Medicine, a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper, the NCBI houses a series of databases relevant to biotechnology and biomedicine and is an important resource for bioinformatics tools and services. Major databases include GenBank for DNA sequences and PubMed, a database for the biomedical literature. Other databases include the NCBI Epigenomics database, all these databases are available online through the Entrez search engine. NCBI is directed by David Lipman, one of the authors of the BLAST sequence alignment program. He also leads a research program, including groups led by Stephen Altschul, David Landsman, Eugene Koonin, John Wilbur, Teresa Przytycka. NCBI is listed in the Registry of Research Data Repositories re3data. org, NCBI has had responsibility for making available the GenBank DNA sequence database since 1992. GenBank coordinates with individual laboratories and other databases such as those of the European Molecular Biology Laboratory. Since 1992, NCBI has grown to other databases in addition to GenBank. The NCBI assigns a unique identifier to each species of organism, the NCBI has software tools that are available by WWW browsing or by FTP. For example, BLAST is a sequence similarity searching program, BLAST can do sequence comparisons against the GenBank DNA database in less than 15 seconds. RAG2/IL2RG The NCBI Bookshelf is a collection of freely accessible, downloadable, some of the books are online versions of previously published books, while others, such as Coffee Break, are written and edited by NCBI staff. BLAST is a used for calculating sequence similarity between biological sequences such as nucleotide sequences of DNA and amino acid sequences of proteins. BLAST is a tool for finding sequences similar to the query sequence within the same organism or in different organisms. It searches the query sequence on NCBI databases and servers and post the results back to the browser in chosen format. Input sequences to the BLAST are mostly in FASTA or Genbank format while output could be delivered in variety of such as HTML, XML formatting. HTML is the output format for NCBIs web-page. Entrez is both indexing and retrieval system having data from sources for biomedical research

3.
Swiss-Prot
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UniProt is a freely accessible database of protein sequence and functional information, many entries being derived from genome sequencing projects. It contains an amount of information about the biological function of proteins derived from the research literature. The UniProt consortium comprises the European Bioinformatics Institute, the Swiss Institute of Bioinformatics, EBI, located at the Wellcome Trust Genome Campus in Hinxton, UK, hosts a large resource of bioinformatics databases and services. SIB, located in Geneva, Switzerland, maintains the ExPASy servers that are a resource for proteomics tools. In 2002, EBI, SIB, and PIR joined forces as the UniProt consortium, each consortium member is heavily involved in protein database maintenance and annotation. Until recently, EBI and SIB together produced the Swiss-Prot and TrEMBL databases and these databases coexisted with differing protein sequence coverage and annotation priorities. Swiss-Prot aimed to provide reliable protein sequences associated with a level of annotation. Recognizing that sequence data were being generated at a pace exceeding Swiss-Prots ability to keep up, meanwhile, PIR maintained the PIR-PSD and related databases, including iProClass, a database of protein sequences and curated families. The consortium members pooled their resources and expertise, and launched UniProt in December 2003. UniProt provides four core databases, UniProtKB, UniParc, UniRef, UniProt Knowledgebase is a protein database partially curated by experts, consisting of two sections, UniProtKB/Swiss-Prot and UniProtKB/TrEMBL. As of 19 March 2014, release 2014_03 of UniProtKB/Swiss-Prot contains 542,782 sequence entries, UniProtKB/Swiss-Prot is a manually annotated, non-redundant protein sequence database. It combines information extracted from literature and biocurator-evaluated computational analysis. The aim of UniProtKB/Swiss-Prot is to all known relevant information about a particular protein. Annotation is regularly reviewed to keep up with current scientific findings, the manual annotation of an entry involves detailed analysis of the protein sequence and of the scientific literature. Sequences from the gene and the same species are merged into the same database entry. Differences between sequences are identified, and their cause documented, a range of sequence analysis tools is used in the annotation of UniProtKB/Swiss-Prot entries. Computer-predictions are manually evaluated, and relevant results selected for inclusion in the entry and these predictions include post-translational modifications, transmembrane domains and topology, signal peptides, domain identification, and protein family classification. Relevant publications are identified by searching databases such as PubMed, the full text of each paper is read, and information is extracted and added to the entry

4.
Locus (genetics)
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A locus in genetics is the position on a chromosome. Each chromosome carries many genes, humans estimated haploid protein coding genes are 19, 000-20,000, a variant of the similar DNA sequence located at a given locus is called an allele. The ordered list of known for a particular genome is called a gene map. Gene mapping is the process of determining the locus for a biological trait. The chromosomal locus of a gene might be written 3p22.1, here 3 means chromosome 3, p means p-arm. And 22 refers to region 2, band 2 and this is read as two two, not as twenty-two. So the entire locus is read as three P two two point one, the cytogenetic bands are counting from the centromere out toward the telomeres. A range of loci is specified in a similar way. For example, the locus of gene OCA1 may be written 11q1. 4-q2.1, meaning it is on the arm of chromosome 11. The ends of a chromosome are labeled pter and qter, a centisome is defined as 1% of a chromosome length. Chromosomal translocation Cytogenetic notation Karyotype Null allele Michael, R. Cummings, belmont, California, Brooks/Cole Overview at ornl. gov Chromosome Banding and Nomenclature from NCBI

5.
Chromosome 11 (human)
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Chromosome 11 is one of the 23 pairs of chromosomes in humans. Humans normally have two copies of this chromosome, Chromosome 11 spans about 135 million base pairs and represents between 4 and 4.5 percent of the total DNA in cells. Identifying genes on each chromosome is an area of genetic research. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies, in January 2017, two estimates differed insignificantly, with one estimate giving 2,920 genes, and the other estimate giving 2,893 genes. At 21.5 genes per megabase, Chromosome 11 is one of the most gene-rich, more than 40% of the 856 olfactory receptor genes in the human genome are located in 28 single-gene, and multi-gene, clusters along this chromosome

6.
Enzyme
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Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase

7.
Glycogen phosphorylase
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Glycogen phosphorylase is one of the phosphorylase enzymes. Glycogen phosphorylase catalyzes the rate-limiting step in glycogenolysis in animals by releasing glucose-1-phosphate from the terminal alpha-1, Glycogen phosphorylase is also studied as a model protein regulated by both reversible phosphorylation and allosteric effects. Glycogen phosphorylase breaks up glycogen into glucose subunits, n + Pi ⇌ n-1 + α-D-glucose-1-phosphate, Glycogen is left with one fewer glucose molecule, and the free glucose molecule is in the form of glucose-1-phosphate. In order to be used for metabolism, it must be converted to glucose-6-phosphate by the enzyme phosphoglucomutase, Glycogen phosphorylase can act only on linear chains of glycogen. Its work will come to a halt four residues away from α1-6 branch. In these situations, an enzyme is necessary, which will straighten out the chain in that area. After all this is done, glycogen phosphorylase can continue and this crevice connects the glycogen storage site to the active, catalytic site. Glycogen phosphorylase has a pyridoxal phosphate at each catalytic site, pyridoxal phosphate links with basic residues and covalently forms a Schiff base. There is also a proposed mechanism involving a positively charged oxygen in a half-chair conformation. The glycogen phosphorylase monomer is a protein, composed of 842 amino acids with a mass of 97.434 kDa in muscle cells. While the enzyme can exist as a monomer or tetramer. In mammals, the major isozymes of glycogen phosphorylase are found in muscle, liver, the brain type is predominant in adult brain and embryonic tissues, whereas the liver and muscle types are predominant in adult liver and skeletal muscle, respectively. The glycogen phosphorylase dimer has many regions of biological significance, including sites, glycogen binding sites, allosteric sites. First, the sites are relatively buried, 15Å from the surface of the protein. Perhaps the most important regulatory site is Ser14, the site of reversible phosphorylation very close to the subunit interface. The structural change associated with phosphorylation, and with the conversion of phosphorylase b to phosphorylase a, is the arrangement of the originally disordered residues 10 to 22 into α helices. This change increases phosphorylase activity up to 25% even in the absence of AMP, the allosteric site of AMP binding on muscle isoforms of glycogen phosphorylase are close to the subunit interface just like Ser14. AMP binding rotates the tower helices of the two subunits 50˚ relative to one another through greater organization and intersubunit interactions, the final, perhaps most curious site on the glycogen phosphorylase protein is the so-called glycogen storage site

8.
Glycogen
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Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in humans, animals, and fungi. The polysaccharide structure represents the main form of glucose in the body. In humans, glycogen is made and stored primarily in the cells of the liver, glycogen functions as the secondary long-term energy storage, with the primary energy stores being fats held in adipose tissue. Muscle glycogen is converted into glucose by muscle cells, and liver glycogen converts to glucose for use throughout the body including the nervous system. Glycogen is the analogue of starch, a polymer that functions as energy storage in plants. It has a similar to amylopectin, but is more extensively branched. Both are white powders in their dry state, glycogen is found in the form of granules in the cytosol/cytoplasm in many cell types, and plays an important role in the glucose cycle. Glycogen forms a reserve that can be quickly mobilized to meet a sudden need for glucose. In the liver, glycogen can make up from 5–6% of the fresh weight. Only the glycogen stored in the liver can be accessible to other organs. In the muscles, glycogen is found in a low concentration, the amount of glycogen stored in the body—especially within the muscles, liver, and red blood cells—mostly depends on physical training, basal metabolic rate, and eating habits. Small amounts of glycogen are found in the kidneys, and even smaller amounts in certain cells in the brain. The uterus also stores glycogen during pregnancy to nourish the embryo, glycogen is a branched biopolymer consisting of linear chains of glucose residues with further chains branching off every 8 to 12 glucoses or so. Glucoses are linked together linearly by α glycosidic bonds from one glucose to the next, branches are linked to the chains from which they are branching off by α glycosidic bonds between the first glucose of the new branch and a glucose on the stem chain. Due to the way glycogen is synthesised, every glycogen granule has at its core a glycogenin protein. Glycogen in muscle, liver, and fat cells is stored in a hydrated form, as a meal containing carbohydrates or protein is eaten and digested, blood glucose levels rise, and the pancreas secretes insulin. Blood glucose from the vein enters liver cells. Insulin acts on the hepatocytes to stimulate the action of several enzymes, glucose molecules are added to the chains of glycogen as long as both insulin and glucose remain plentiful

9.
Carbohydrate
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A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohydrates are technically hydrates of carbon, structurally it is accurate to view them as polyhydroxy aldehydes and ketones. The term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars, starch, the saccharides are divided into four chemical groups, monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars. The word saccharide comes from the Greek word σάκχαρον, meaning sugar, while the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose. For example, grape sugar is the glucose, cane sugar is the disaccharide sucrose. Carbohydrates perform numerous roles in living organisms, polysaccharides serve for the storage of energy and as structural components. The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA, the related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the system, fertilization, preventing pathogenesis, blood clotting. In food science and in informal contexts, the term carbohydrate often means any food that is particularly rich in the complex carbohydrate starch or simple carbohydrates. Often in lists of information, such as the USDA National Nutrient Database, the term carbohydrate is used for everything other than water, protein, fat, ash. This will include chemical compounds such as acetic or lactic acid, carbohydrates are found in wide variety of foods. The important sources are cereals, potatoes, sugarcane, fruits, table sugar, bread, milk, starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other cereals, sugar appears in our diet mainly as sucrose which is added to drinks and many prepared foods such as jam, biscuits and cakes. Glucose and fructose are found naturally in fruits and some vegetables. Glycogen is carbohydrate found in the liver and muscles, cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fibre which helps to maintain a healthy digestive system, formerly the name carbohydrate was used in chemistry for any compound with the formula Cm n

10.
Muscle cell
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A myocyte is the type of cell found in muscle tissue. Myocytes are long, tubular cells that develop from myoblasts to form muscles in a known as myogenesis. There are various specialized forms of myocytes, cardiac, skeletal, the striated cells of cardiac and skeletal muscles are referred to as muscle fibers. Cardiomyocytes are the fibres that form the chambers of the heart. Skeletal muscle fibers help support and move the body and tend to have peripheral nuclei, smooth muscle cells control involuntary movements such as the peristalsis contractions in the oesophagus and stomach. The unusual microstructure of muscle cells has led biologists to create specialized terminology. However, each specific to muscle cells has a counterpart that is used in the terminology applied to other types of cells. Most of the sarcoplasm is filled with myofibrils, which are long protein cords composed of myofilaments, there are three types of myofilaments, Thick filaments, composed of protein molecules called myosin. In striations of muscle bands, these are the filaments that make up the A band. Thin filaments are composed of molecules called actin. In striations of muscle bands, these are the filaments that make up the I band. Elastic filaments are composed of titin, a large springy protein, together, these myofilaments work to produce a muscle contraction. The sarcoplasmic reticulum, a type of smooth endoplasmic reticulum. The sarcolemma is the membrane of a striated muscle fiber and receives. At the end of each fiber, the outer layer of the sarcolemma combines with tendon fibers. The cell membrane of a myocyte has several specialized regions, which may include the intercalated disk, the cell membrane is covered by a lamina coat which is approximately 50 nm wide. The laminar coat is separable into two layers, the lamina densa and lamina lucida, in between these two layers can be several different types of ions, including calcium. The cell membrane is anchored to the cytoskeleton by anchor fibers that are approximately 10 nm wide

11.
Astrocyte
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Astrocytes, also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. The proportion of astrocytes in the brain is not well defined, depending on the counting technique used, studies have found that the astrocyte proportion varies by region and ranges from 20% to 40% of all glia. Astrocytes are a type of cells and they hold various roles. Data suggest that astrocytes also signal to neurons through Ca2+-dependent release of glutamate, such discoveries have made astrocytes an important area of research within the field of neuroscience. Astrocytes are a sub-type of glial cells in the nervous system. They are also known as astrocytic glial cells, star-shaped, their many processes envelop synapses made by neurons. Astrocytes are classically identified using histological analysis, many of these express the intermediate filament glial fibrillary acidic protein. Several forms of astrocytes exist in the nervous system including fibrous, protoplasmic. The fibrous glia are located within white matter, have relatively few organelles. This type often has vascular feet that physically connect the cells to the outside of capillary walls when they are in proximity to them. The protoplasmic glia are the most prevalent and are found in grey matter tissue, possess a quantity of organelles. The radial glia are disposed in planes perpendicular to the axes of ventricles, one of their processes abuts the pia mater, while the other is deeply buried in gray matter. Radial glia are mostly present during development, playing a role in neuron migration, müller cells of the retina and Bergmann glia cells of the cerebellar cortex represent an exception, being present still during adulthood. When in proximity to the pia mater, all three forms of astrocytes send out processes to form the pia-glial membrane, Astrocytes are macroglial cells in the central nervous system. Astrocytes are derived from heterogeneous populations of cells in the neuroepithelium of the developing central nervous system. The resultant patterning along the neuraxis leads to segmentation of the neuroepithelium into progenitor domains for distinct types in the developing spinal cord. On the basis of several studies it is now believed that model also applies to macroglial cell specification. Studies carried out by Hochstim and colleagues have demonstrated that three distinct populations of astrocytes arise from the p1, p2 and p3 domains, previously in medical science, the neuronal network was considered the only important function of astrocytes, and they were looked upon as gap fillers

12.
PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby

13.
Medical Subject Headings
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Medical Subject Headings is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences, it serves as a thesaurus that facilitates searching. Created and updated by the United States National Library of Medicine, it is used by the MEDLINE/PubMed article database, MeSH is also used by ClinicalTrials. gov registry to classify which diseases are studied by trials registered in ClinicalTrials. gov. MeSH was introduced in 1960, with the NLMs own index catalogue, the yearly printed version of MeSH was discontinued in 2007 and MeSH is now available online only. It can be browsed and downloaded free of charge through PubMed, originally in English, MeSH has been translated into numerous other languages and allows retrieval of documents from different languages. The 2009 version of MeSH contains a total of 25,186 subject headings, most of these are accompanied by a short description or definition, links to related descriptors, and a list of synonyms or very similar terms. This additional information and the structure make the MeSH essentially a thesaurus. The descriptors or subject headings are arranged in a hierarchy, a given descriptor may appear at several locations in the hierarchical tree. The tree locations carry systematic labels known as numbers. The tree numbers of a given descriptor are subject to change as MeSH is updated, every descriptor also carries a unique alphanumerical ID that will not change. Most subject headings come with a description or definition. See the MeSH description for diabetes type 2 as an example, the explanatory text is written by the MeSH team based on their standard sources if not otherwise stated. References are mostly encyclopaedias and standard textbooks of the subject areas, references for specific statements in the descriptions are not given, instead readers are referred to the bibliography. In addition to the hierarchy, MeSH contains a small number of standard qualifiers. For example, Measles is a descriptor and epidemiology is a qualifier, the epidemiology qualifier can be added to all other disease descriptors. Not all descriptor/qualifier combinations are allowed some of them may be meaningless. In all there are 83 different qualifiers, in addition to the descriptors, MeSH also contains some 139,000 supplementary concept records. These do not belong to the vocabulary as such, instead they enlarge the thesaurus. Many of these records describe chemical substances, by default, a search for a descriptor will include all the descriptors in the hierarchy below the given one

14.
Transferase
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A transferase is any one of a class of enzymes that enact the transfer of specific functional groups from one molecule to another. They are involved in hundreds of different biochemical pathways throughout biology, transferases are involved in myriad reactions in the cell. Transferases are also utilized during translation, in this case, an amino acid chain is the functional group transferred by a peptidyl transferase. Group would be the group transferred as a result of transferase activity. The donor is often a coenzyme, some of the most important discoveries relating to transferases occurred as early as the 1930s. Earliest discoveries of transferase activity occurred in other classifications of enzymes, including Beta-galactosidase, protease, prior to the realization that individual enzymes were capable of such a task, it was believed that two or more enzymes enacted functional group transfers. This observance was later verified by the discovery of its reaction mechanism by Braunstein and their analysis showed that this reversible reaction could be applied to other tissues. This assertion was validated by Rudolf Schoenheimers work with radioisotopes as tracers in 1937 and this in turn would pave the way for the possibility that similar transfers were a primary means of producing most amino acids via amino transfer. Another such example of early research and later reclassification involved the discovery of uridyl transferase. In 1953, the enzyme UDP-glucose pyrophosphorylase was shown to be a transferase, when it was found that it could reversibly produce UTP and G1P from UDP-glucose, another example of historical significance relating to transferase is the discovery of the mechanism of catecholamine breakdown by catechol-O-methyltransferase. This discovery was a part of the reason for Julius Axelrod’s 1970 Nobel Prize in Physiology or Medicine. Classification of transferases continues to this day, with new ones being discovered frequently, an example of this is Pipe, a sulfotransferase involved in the dorsal-ventral patterning of Drosophilia. Initially, the mechanism of Pipe was unknown, due to a lack of information on its substrate. Research into Pipes catalytic activity eliminated the likelihood of it being a heparan sulfate glycosaminoglycan, further research has shown that Pipe targets the ovarian structures for sulfation. Pipe is currently classified as a Drosophilia heparan sulfate 2-O-sulfotransferase, systematic names of transferases are constructed in the form of donor, acceptor grouptransferase. For example, a DNA methyltransferase is a transferase that catalyzes the transfer of a group to a DNA acceptor. In practice, many molecules are not referred to using this terminology due to more prevalent common names, in the EC system of classification, the accepted name for RNA Polymerase is DNA-directed RNA polymerase. Described primarily based on the type of biochemical group transferred, transferases can be divided into ten categories and these categories comprise over 450 different unique enzymes

15.
Glycosyltransferase
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Glycosyltransferases are enzymes that establish natural glycosidic linkages. The result of transfer can be a carbohydrate, glycoside, oligosaccharide. Some glycosyltransferases catalyse transfer to inorganic phosphate or water, glycosyl transfer can also occur to protein residues, usually to tyrosine, serine, or threonine to give O-linked glycoproteins, or to asparagine to give N-linked glycoproteins. Mannosyl groups may be transferred to tryptophan to generate C-mannosyl tryptophan, transferases may also use lipids as an acceptor, forming glycolipids, and even use lipid-linked sugar phosphate donors, such as dolichol phosphates. Glycosyltransferases that utilize non-nucleotide donors such as dolichol or polyprenol pyrophosphate are non-Leloir glycosyltransferases, the phosphate of these donor molecules are usually coordinated by divalent cations such as manganese, however metal independent enzymes exist. Glycosyltransferases can be segregated into “retaining” or“ inverting” enzymes according to whether the stereochemistry of the donor’s anomeric bond is retained or inverted during the transfer, the inverting mechanism is straightforward, requiring a single nucleophilic attack from the accepting atom to invert stereochemistry. The retaining mechanism has been a matter of debate, but there exists strong evidence against a double displacement mechanism or a dissociative mechanism, sequence-based classification methods have proven to be a powerful way of generating hypotheses for protein function based on sequence alignment to related proteins. The carbohydrate-active enzyme database presents a classification of glycosyltransferases into over 90 families. The same three-dimensional fold is expected to occur within each of the families, in contrast to the diversity of 3D structures observed for glycoside hydrolases, glycosyltransferase have a much smaller range of structures. Many inhibitors of glycosyltransferases are known, some glycosyltransferase inhibitors are of use as drugs or antibiotics. Moenimycin is used in animal feed as a growth promoter, caspofungin has been developed from the echinocandins and is in use as an antifungal agent. Ethambutol is an inhibitor of mycobacterial arabinotransferases and is used for the treatment of tuberculosis, lufenuron is an inhibitor of insect chitin synthases and is used to control fleas in animals. The ABO blood group system is determined by type of glucosyltransferases are expressed in the body. The ABO gene locus expressing the glucosyltransferases has three main forms, A, B, and O. The A allele encodes 1-3-N-acetylgalactosaminyltransferase that bonds α-N-acetylgalactosamine to D-galactose end of H antigen, the B allele encodes 1-3-galactosyltransferase that joins α-D-galactose bonded to D-galactose end of H antigen, creating the B antigen. In case of O allele the exon 6 contains a deletion that results in a loss of enzymatic activity, the O allele differs slightly from the A allele by deletion of a single nucleotide - Guanine at position 261. The deletion causes a frameshift and results in translation of an almost entirely different protein that lacks enzymatic activity and this results in H antigen remaining unchanged in case of O groups. The combination of glucosyltransferases by both present in each person determines whether there is an AB, A, B or O blood type

16.
Glycogen synthase
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Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase that catalyses the reaction of UDP-glucose and n to yield UDP, in other words, this enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen. Glycogen synthase concentration is highest in the bloodstream 30 to 60 minutes following intense exercise, much research has been done on glycogen degradation through studying the structure and function of glycogen phosphorylase, the key regulatory enzyme of glycogen degradation. On the other hand, much less is known about the structure of glycogen synthase, the crystal structure of glycogen synthase from Agrobacterium tumefaciens, however, has been determined at 2.3 A resolution. In its asymmetric form, glycogen synthase is found as a dimer and this structural property, among others, is shared with related enzymes, such as glycogen phosphorylase and other glycosyltransferases of the GT-B superfamily. Nonetheless, a more recent characterization of the Saccharomyces cerevisiae glycogen synthase crystal structure reveals that the dimers may actually interact to form a tetramer, since the structure of eukaryotic glycogen synthase is highly conserved among species, glycogen synthase likely forms a tetramer in humans as well. Glycogen synthase can be classified in two protein families. The first family, which is from mammals and yeast, is approximately 80 kDa, uses UDP-glucose as a sugar donor, the second family, which is from bacteria and plants, is approximately 50 kDA, uses ADP-glucose as a sugar donor, and is unregulated. Glycogen synthase catalyzes the conversion of the moiety of uridine diphosphate glucose into glucose to be incorporated into glycogen via an α glycosidic bond. However, since glycogen synthase requires an oligosaccharide primer as a glucose acceptor, in a recent study of transgenic mice, an overexpression of glycogen synthase and an overexpression of phosphatase both resulted in excess glycogen storage levels. This suggests that glycogen synthase plays an important biological role in regulating glycogen/glucose levels and is activated by dephosphorylation, in humans, there are two paralogous isozymes of glycogen synthase, The liver enzyme expression is restricted to the liver, whereas the muscle enzyme is widely expressed. Liver glycogen serves as a pool to maintain the blood glucose level during fasting. The role of muscle glycogen is as a reserve to provide energy during bursts of activity, meanwhile, the muscle isozyme plays a major role in the cellular response to long-term adaptation to hypoxia. Notably, hypoxia only induces expression of the muscle isozyme and not the liver isozyme, however, muscle-specific glycogen synthase activation may lead to excessive accumulation of glycogen, leading to damage in the heart and central nervous system following ischemic insults. Phosphorylation of glycogen synthase decreases its activity, the enzyme also cleaves the ester bond between the C1 position of glucose and the pyrophosphate of UDP itself. The control of glycogen synthase is a key step in regulating glycogen metabolism, glycogen synthase is directly regulated by glycogen synthase kinase 3, AMPK, protein kinase A, and casein kinase 2. Each of these protein kinases lead to phosphorylated and catalytically inactive glycogen synthase, the phosphorylation sites of glycogen synthase are summarized below. For enzymes in the GT3 family, these regulatory kinases inactivate glycogen synthase by phosphorylating it at the N-terminal of the 25th residue, glycogen synthase is also regulated by protein phosphatase 1, which activates glycogen synthase via dephosphorylation

17.
Glycogen debranching enzyme
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A debranching enzyme is a molecule that helps facilitate the breakdown of glycogen, which serves as a store of glucose in the body, through glucosyltransferase and glucosidase activity. Together with phosphorylases, debranching enzymes mobilize glucose reserves from glycogen deposits in the muscles and this constitutes a major source of energy reserves in most organisms. Glycogen breakdown is highly regulated in the body, especially in the liver, by various hormones including insulin and glucagon, when glycogen breakdown is compromised by mutations in the glycogen debranching enzyme, metabolic diseases such as Glycogen storage disease type III can result. Glucosyltransferase and glucosidase are performed by an enzyme in mammals, yeast, and some bacteria. Proteins that catalyze both functions are referred to as glycogen debranching enzymes, when glucosyltransferase and glucosidase are catalyzed by distinct enzymes, glycogen debranching enzyme usually refers to the glucosidase enzyme. In some literature, an enzyme capable only of glucosidase is referred to as a debranching enzyme, together with phosphorylase, glycogen debranching enzymes function in glycogen breakdown and glucose mobilization. When phosphorylase has digested a glycogen branch down to four glucose residues, Glycogen debranching enzymes assist phosphorylase, the primary enzyme involved in glycogen breakdown, mobilize glycogen stores. Phosphorylase can only cleave α-1, 4- glycosidic bond between adjacent glucose molecules in glycogen but branches exist as α-1,6 linkages. The mechanism by which the glucosidase cleaves the α -1, 6-linkage is not fully known because the amino acids in the site have not yet been identified. It is thought to proceed through a two step acid base assistance type mechanism, with an oxocarbenium ion intermediate, and retention of configuration in glucose. This is a method through which to cleave bonds, with an acid below the site of hydrolysis to lend a proton. These acids and bases are amino acid chains in the active site of the enzyme. A scheme for the mechanism is shown in the figure below, thus the debranching enzymes, transferase and α-1, 6- glucosidase converts the branched glycogen structure into a linear one, paving the way for further cleavage by phosphorylase. In E. coli and other bacteria, glucosyltransferase and glucosidase functions are performed by two distinct enzymes, in E. coli, Glucose transfer is performed by 4-alpha-glucanotransferase, a 78.5 kDa protein coded for by the gene malQ. A second protein, referred to as debranching enzyme, performs α-1 and this enzyme has a molecular mass of 73.6 kDa, and is coded for by the gene glgX. Activity of the two enzymes is not always necessarily coupled, in E. coli glgX selectively catalyzes the cleavage of 4-subunit branches, without the action of glucanotransferase. The product of cleavage, maltotetraose, is further degraded by maltodextrin phosphorylase. E. coli GlgX is structurally similar to the protein isoamylase, the monomeric protein contains a central domain in which eight parallel beta-strands are surrounded by eight parallel alpha strands

18.
Glycogen branching enzyme
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Glycogen branching enzyme is an enzyme that adds branches to the growing glycogen molecule during the synthesis of glycogen, a storage form of glucose. More specifically, during synthesis, a glucose 1-phosphate molecule reacts with uridine triphosphate to become UDP-glucose. Importantly, glycogen synthase can only catalyze the synthesis of α-1, branching also importantly increases the solubility and decreases the osmotic strength of glycogen. This enzyme belongs to the family of transferases, to be specific, the systematic name of this enzyme class is 1, 4-alpha-D-glucan,1, 4-alpha-D-glucan 6-alpha-D--transferase. This enzyme participates in starch and sucrose metabolism, GBE is encoded by the GBE1 gene. Through southern blot analysis of DNA derived from human/rodent somatic cell hybrids, the human GBE gene was also isolated by a function complementation of the Saccharomyces cerevisiae GBE deficiency. From the isolated cDNA, the length of the gene was found to be approximately 3 kb, additionally, the coding sequence was found to comprise 2,106 base pairs and encode a 702-amino acid long GBE. The molecular mass of human GBE was calculated to be 80,438 Da, glycogen branching enzyme belongs to the α-amylase family of enzymes, which include α-amylases, pullulanas/isoamylase, cyclodextrin glucanotransferase, and branching enzyme. While the central domain is common in members of the α-amylase family. Additionally, there are striking differences between the loops connecting elements of the secondary structure among these various α-amylase members, especially around the active site. In comparison to the family members, glycogen binding enzyme has shorter loops. These residues are implicated in catalysis and substrate binding, glycogen binding enzymes in other organisms have also been crystallized and structurally determined, demonstrating both similarity and variation to GBE found in Escherichia coli. In glycogen, every 10 to 14 glucose units, a branch with an additional chain of glucose units occurs. The side chain attaches at carbon atom 6 of a glucose unit and this connection is catalyzed by a branching enzyme, generally given the name α-glucan branching enzyme. A branching enzyme attaches a string of seven glucose units to the carbon at the C-6 position on the unit, forming the α-1. The specific nature of this means that this chain of 7 carbons is usually attached to a glucose molecule that is in position three from the non-reducing end of another chain. Mutations in this gene are associated with glycogen storage disease type IV in newborns, approximately 40 mutations in the GBE1 gene, most resulting in a point mutation in the glycogen branching enzyme, have led to the early childhood disorder, glycogen storage disease type IV. This disease is characterized by a severe depletion or complete absence of GBE, resulting in the accumulation of abnormally structured glycogen, glycogen buildup leads to increased osmotic pressure resulting in cellular swelling and death

19.
Galactosyltransferase
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Galactosyltransferase is a type of glycosyltransferase which catalyzes the transfer of galactose. The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases and these enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. This classification is available on the CAZy web site, the same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form clans

20.
Glucuronosyltransferase
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Uridine 5-diphospho-glucuronosyltransferase is a cytosolic glycosyltransferase that catalyzes the transfer of the glucuronic acid component of UDP-glucuronic acid to a small hydrophobic molecule. Alternative names, glucuronyltransferase UDP-glucuronyl transferase UDP-GT Glucuronosyltransferases are responsible for the process of glucuronidation, arguably the most important of the Phase II enzymes, UGTs have been the subject of increasing scientific inquiry since the mid-to-late 1990s. It is also the pathway for foreign chemical removal for most drugs, dietary substances, toxins. UGT is present in humans, other animals, plants, famously, UGT enzymes are not present in the genus Felis, and this accounts for a number of unusual toxicities in the cat family. The resulting glucuronide is more polar and more easily excreted than the substrate molecule, the product solubility in blood is increased allowing it to be eliminated from the body by the kidneys. A deficiency in the specific form of glucuronosyltransferase is thought to be the cause of Gilberts syndrome. It is also associated with Crigler-Najjar syndrome, a serious disorder where the enzymes activity is either completely absent or less than 10% of normal. Infants may have a deficiency in UDP-glucuronyl transferase, and are unable to hepatically metabolize the antibiotic drug chloramphenicol which requires glucuronidation. This leads to a known as gray baby syndrome

21.
B3GAT1
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Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 1, or CD57, is an enzyme that in humans is encoded by the B3GAT1 gene. In immunology, the CD57 antigen is known as HNK1 or LEU7. It is expressed as an epitope that contains a sulfoglucuronyl residue in several adhesion molecules of the nervous system. The protein encoded by this gene is a member of the gene family. These enzymes exhibit strict acceptor specificity, recognizing nonreducing terminal sugars and this gene product functions as the key enzyme in a glucuronyl transfer reaction during the biosynthesis of the carbohydrate epitope HNK-1. Alternate transcriptional splice variants have been characterized, in anatomical pathology, CD57 is similar to CD56 for use in differentiating neuroendocrine tumors from others. Using immunohistochemistry, CD57 molecule can be demonstrated in around 10 to 20% of lymphocytes, as well as in some epithelial, neural, and chromaffin cells. Among lymphocytes, CD57 positive cells are typically either T cells or NK cells, and are most commonly found within the germinal centres of lymph nodes, tonsils, increased CD57+ counts have also been reported in rheumatoid arthritis and Feltys syndrome, among other conditions. Neoplastic CD57 positive cells are seen in conditions as varied as large granular lymphocytic leukaemia, small-cell carcinoma, thyroid carcinoma, CD57 Antigen at the US National Library of Medicine Medical Subject Headings Human B3GAT1 genome location and B3GAT1 gene details page in the UCSC Genome Browser

Entrez
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The name Entrez was chosen to reflect the spirit of welcoming the public to search the content available from the NLM. Entrez Global Query is a search and retrieval system that provides access to all databases simultaneously with a single query string. Entrez can efficiently retrieve related sequences, structures, and references, the Entrez system

1.
The NCBI Entrez CD-ROM c. 1996

2.
The Entrez logo

National Center for Biotechnology Information
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The National Center for Biotechnology Information is part of the United States National Library of Medicine, a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper, the NCBI houses a series of databases relevant to biotechnology and biom

1.
National Center for Biotechnology Information logo

Swiss-Prot
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UniProt is a freely accessible database of protein sequence and functional information, many entries being derived from genome sequencing projects. It contains an amount of information about the biological function of proteins derived from the research literature. The UniProt consortium comprises the European Bioinformatics Institute, the Swiss Ins

1.
UniProt

Locus (genetics)
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A locus in genetics is the position on a chromosome. Each chromosome carries many genes, humans estimated haploid protein coding genes are 19, 000-20,000, a variant of the similar DNA sequence located at a given locus is called an allele. The ordered list of known for a particular genome is called a gene map. Gene mapping is the process of determin

Chromosome 11 (human)
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Chromosome 11 is one of the 23 pairs of chromosomes in humans. Humans normally have two copies of this chromosome, Chromosome 11 spans about 135 million base pairs and represents between 4 and 4.5 percent of the total DNA in cells. Identifying genes on each chromosome is an area of genetic research. Because researchers use different approaches to g

1.
Pair of human chromosome 11 (after G-banding). One is from mother, one is from father.

Enzyme
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Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to o

Glycogen phosphorylase
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Glycogen phosphorylase is one of the phosphorylase enzymes. Glycogen phosphorylase catalyzes the rate-limiting step in glycogenolysis in animals by releasing glucose-1-phosphate from the terminal alpha-1, Glycogen phosphorylase is also studied as a model protein regulated by both reversible phosphorylation and allosteric effects. Glycogen phosphory

Glycogen
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Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in humans, animals, and fungi. The polysaccharide structure represents the main form of glucose in the body. In humans, glycogen is made and stored primarily in the cells of the liver, glycogen functions as the secondary long-term energy storage, with the

1.
A view of the atomic structure of a single branched strand of glucose units in a glycogen molecule.

2.
Schematic two-dimensional cross-sectional view of glycogen: A core protein of glycogenin is surrounded by branches of glucose units. The entire globular granule may contain around 30,000 glucose units.

Carbohydrate
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A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohyd

1.
Grain products: rich sources of carbohydrates

Muscle cell
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A myocyte is the type of cell found in muscle tissue. Myocytes are long, tubular cells that develop from myoblasts to form muscles in a known as myogenesis. There are various specialized forms of myocytes, cardiac, skeletal, the striated cells of cardiac and skeletal muscles are referred to as muscle fibers. Cardiomyocytes are the fibres that form

Astrocyte
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Astrocytes, also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. The proportion of astrocytes in the brain is not well defined, depending on the counting technique used, studies have found that the astrocyte proportion varies by region and ranges from 20% to 40% of all glia. Astrocytes are a

1.
An astrocytic cell from rat brain grown in tissue culture and stained with antibodies to GFAP (red) and vimentin (green). Both proteins are present in large amounts in the intermediate filaments of this cell, so the cell appears yellow. The blue material shows DNA visualized with DAPI stain, and reveals the nuclei of the astrocyte and other cells.

PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the

1.
PubMed

Medical Subject Headings
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Medical Subject Headings is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences, it serves as a thesaurus that facilitates searching. Created and updated by the United States National Library of Medicine, it is used by the MEDLINE/PubMed article database, MeSH is also used by ClinicalTri

1.
Medical Subject Headings

Transferase
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A transferase is any one of a class of enzymes that enact the transfer of specific functional groups from one molecule to another. They are involved in hundreds of different biochemical pathways throughout biology, transferases are involved in myriad reactions in the cell. Transferases are also utilized during translation, in this case, an amino ac

1.
Reaction involving aspartate transcarbamylase.

2.
RNA Polymerase from Saccharomyces cerevisiae complexed with α-amanitin (in red). Despite the use of the term "polymerase," RNA Polymerases are classified as a form of nucleotidyl transferase.

Glycosyltransferase
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Glycosyltransferases are enzymes that establish natural glycosidic linkages. The result of transfer can be a carbohydrate, glycoside, oligosaccharide. Some glycosyltransferases catalyse transfer to inorganic phosphate or water, glycosyl transfer can also occur to protein residues, usually to tyrosine, serine, or threonine to give O-linked glycoprot

1.
Most glycosyltransferase enzymes form one of two folds: GT-A or GT-B

Glycogen synthase
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Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase that catalyses the reaction of UDP-glucose and n to yield UDP, in other words, this enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen. Glycogen synthase concentration is highest in t

Glycogen debranching enzyme
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A debranching enzyme is a molecule that helps facilitate the breakdown of glycogen, which serves as a store of glucose in the body, through glucosyltransferase and glucosidase activity. Together with phosphorylases, debranching enzymes mobilize glucose reserves from glycogen deposits in the muscles and this constitutes a major source of energy rese

1.
Image of debranching enzyme in E. Coli

Galactosyltransferase
–
Galactosyltransferase is a type of glycosyltransferase which catalyzes the transfer of galactose. The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases and these enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor mole

1.
galactose

Glucuronosyltransferase
–
Uridine 5-diphospho-glucuronosyltransferase is a cytosolic glycosyltransferase that catalyzes the transfer of the glucuronic acid component of UDP-glucuronic acid to a small hydrophobic molecule. Alternative names, glucuronyltransferase UDP-glucuronyl transferase UDP-GT Glucuronosyltransferases are responsible for the process of glucuronidation, ar

1.
Structure of TDP-vancosaminyltransferase GtfD as a complex with TDP and the natural substrate, desvancosaminyl vancomycin.

B3GAT1
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Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 1, or CD57, is an enzyme that in humans is encoded by the B3GAT1 gene. In immunology, the CD57 antigen is known as HNK1 or LEU7. It is expressed as an epitope that contains a sulfoglucuronyl residue in several adhesion molecules of the nervous system. The protein encoded by this gene

1.
The enzyme TEV protease contains an example of a catalytic triad of residues (red) in its active site. The triad consists of an Aspartic acid (Acid), histidine (Base) and cysteine (Nuc). The substrate (black) is bound by the binding site to orient it next to the triad. PDB: 1lvm ​

1.
An illustration to show (a) Alberty-Hammes-Eigen model, and (b) Chou’s model, where E denotes the enzyme whose active site is colored in red, while the substrate S in blue.

2.
The distribution of known enzyme catalytic rates (k cat /K M). Most enzymes have a rate around 10 5 s −1 M −1. The fastest enzymes in the dark box on the right (>10 8 s −1 M −1) are constrained by the diffusion limit. (Data adapted from reference)

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Robots used for the high-throughput screening of chemical libraries to discover new enzyme inhibitors

2.
HIV protease in a complex with the protease inhibitor ritonavir. The structure of the protease is shown by the red, blue and yellow ribbons. The inhibitor is shown as the smaller ball-and-stick structure near the center. Created from PDB 1HXW.

1.
Dihydrofolate reductase from E. coli with its two substrates dihydrofolate (right) and NADPH (left), bound in the active site. The protein is shown as a ribbon diagram, with alpha helices in red, beta sheets in yellow and loops in blue. Generated from 7DFR.